Degradation pathways of decabromodiphenyl ether during hydrothermal treatment

Nose, K.; Hashimoto, S.; Takahashi, S.; Noma, Y.; Sakai, S. (2007) Chemosphere, 68(1): 120-125

The hydrothermal degradation pathways of decabromodiphenyl ether during hydrothermal treatment were investigated. After an initial ""Heating time"", the reaction runs were carried out at constant temperature (heating to 300 C-deg and keeping temperature) and pressure (8 MPa) in a SUS316 stainless steel micro autoclave filled with water. Some decomposition of decabromodiphenyl ether was observed over 200 C-deg, and it was decomposed by more than 99% after 10 min at 300 C-deg. The reactivities of bromine on para and meta substituents were relatively high, while its reactivity on ortho bromine was extremely low. The formations of polybrominated dibenzo-p-dioxins and furans (PBDD/DFs) were observed in the early stages of the reactions at around 300 C-deg. The TCDD toxicity equivalency (TCDD-EQs) of the by-products was determined based on relative potencies (REPs EC5TCDD) with the Dioxin-Responsive-Chemical Activated Luciferase gene eXpression (DR-CALUX) bioassays technology. These results indicated that the risk of formation of PBDD/DFs in the hydrothermal degradation of deca-BDE was low, and it would be possible to reduce the TCDD-EQs value by adding some catalyst or alkali, or extending processing time.


Decomposition; Dioxin-like toxicity; PBDEs; PBDD/DFs; By-product; HRGC-HRMS;